This invention relates to monitoring a signal passed across a window. When the window encounters an obstruction, the signal will change and an indication then be made that an obstruction is in the window path.
Modern vehicles typically have several windows which are movable automatically. In this application, the term "window" should be understood to include not only side windows in the vehicle, but also other moveable closures such as rear windows, sunroofs, etc.
Typically, in the prior art, a switch may be actuated, and the window will then close automatically. There are sometimes obstructions in the way of the window. As an example, a passenger's arm may extend outwardly of the window opening when the window is being closed.
The prior art has attempted to identify such obstructions by monitoring the current or torque load on the motor. When a particular characteristic of the load on the motor is seen, an indication is made that an obstruction has been encountered.
It would be desirable to provide an indicator of an obstruction which is more directly related to the window and its contact with an obstruction.